Fig. 6. P2 receptor expression. (A) RT-PCR. Neurospheres (NS) express mRNA for P2Y₁, P2Y₂ and P2Y₆ receptors, but not for the P2Y₄ receptor. A P2Y₄ PCR product could, however, be amplified from a mouse brain genomic DNA preparation (gDNA). To exclude contamination of the mRNA preparation with genomic DNA, a primer pair for the immunoglobulin heavy chain binding protein (BiP) was used. Using the mRNA preparation from the neurospheres (NS), a 560 bp sequence was amplified. With mouse brain genomic DNA (gDNA), a 876 bp PCR product was amplified that contained a 316 bp long intron sequence. (B) In situ hybridization. Left: Using a 319 bp fragment of the P2Y₁ receptor as an antisense probe, mRNA was detected in large cell bodies of the striatum and in select clusters of subependymal cells (arrows) of the lateral wall of the lateral ventricle (lv), as well as in the dorsolateral triangular area of the SVZ (arrowheads), where neuroblasts enter the RMS. A cluster of labeled subependymal cells boxed in the left image is enlarged in the middle panel. Right: Lack of staining for the corresponding sense probe. Scale bars: 50 µm in the left and right panels; 10 µm in the middle panel.